using Antlr4.Runtime;
using Antlr4.Runtime.Atn;
using Rubberduck.Parsing.Grammar;

namespace Rubberduck.Parsing.Parsers;

public sealed class VBAExpressionParser
{
    /// <summary>
    /// Parses the given VBA expression.
    /// </summary>
    /// <param name="expression">The expression to parse. NOTE: Call statements are not supported.</param>
    /// <returns>The root of the parse tree.</returns>
    public ParserRuleContext Parse(string expression)
    {
        var stream = new AntlrInputStream(expression);
        var lexer = new VBALexer(stream);
        var tokens = new CommonTokenStream(lexer);
        var parser = new VBAParser(tokens);

        ParserRuleContext tree;
        try
        {
            parser.Interpreter.PredictionMode = PredictionMode.Sll;
            tree = parser.expression();
        }
        catch
        {
            tokens.Reset();
            parser.Reset();
            parser.Interpreter.PredictionMode = PredictionMode.Ll;
            tree = parser.expression();
        }
        return tree;
    }
}
